Estimated Phytoplankton Size

Figure. Estimated Median Phytoplankton Size from satellite. The map (top) shows the change in the estimated median phytoplankton size (μm equivalent spherical diameter, ESD) in the vicinity of Palau over the period 1998-2023 derived from satellite remotely sensed sea surface temperature and ocean color data. The grey line is the Palau EEZ. The line plot (bottom) shows the change in the estimated median phytoplankton size (μm ESD) averaged over the area within the top plot. The black line represents the trend, which is not statistically significant (p > 0.05).

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import warnings
warnings.filterwarnings("ignore")
import os
import os.path as op
import sys

import pandas as pd
import numpy as np
import xarray as xr
import geopandas as gpd
import cartopy.crs as ccrs
import matplotlib.pyplot as plt
from myst_nb import glue 

sys.path.append("../../../../indicators_setup")

from ind_setup.plotting_int import plot_timeseries_interactive, plot_oni_index_th
from ind_setup.plotting import plot_base_map, plot_map_subplots, add_oni_cat, plot_bar_probs, fontsize

sys.path.append("../../../functions")
from data_downloaders import download_ERDDAP_data, download_oni_index

Setup

Define area of interest

#Area of interest
lon_range  = [129.4088, 137.0541]
lat_range = [1.5214, 11.6587]

EEZ shapefile

shp_f = op.join(os.getcwd(), '..', '..','..', 'data/Palau_EEZ/pw_eez_pol_april2022.shp')
shp_eez = gpd.read_file(shp_f)

Download Data

DATASET: https://oceanwatch.pifsc.noaa.gov/erddap/info/md50_exp/index.html

update_data = False
path_data = "../../../data"
path_figs = "../../../matrix_cc/figures"

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base_url = 'https://oceanwatch.pifsc.noaa.gov/erddap/griddap/md50_exp.csv'
dataset_id = 'MD50'

if update_data:
    date_ini = '1998-01-01T00:00:00Z'
    date_end = '2024-12-01T00:00:00Z'
    data = download_ERDDAP_data(base_url, dataset_id, date_ini, date_end, lon_range, lat_range)
    data_xr = data.set_index(['latitude', 'longitude', 'time']).to_xarray()
    data_xr['time'] = pd.to_datetime(data_xr.time)
    data_xr = data_xr.coarsen(longitude=2, latitude=2, boundary = 'pad').mean()
    data_xr.to_netcdf(op.join(path_data, f'griddap_{dataset_id}.nc'))
else:
    data_xr = xr.open_dataset(op.join(path_data, f'griddap_{dataset_id}.nc'))

Analysis

Plotting

Average

fig, ax = plot_base_map(shp_eez = shp_eez, figsize = [10, 6])
im = ax.pcolor(data_xr.longitude, data_xr.latitude, data_xr.mean(dim='time')[dataset_id], transform=ccrs.PlateCarree(), 
                cmap = 'YlGnBu', vmin = 0.8, vmax = 1.3)
ax.set_extent([lon_range[0], lon_range[1], lat_range[0], lat_range[1]], crs=ccrs.PlateCarree())
plt.colorbar(im, ax=ax, label='Phytoplankton size MD50 (µm ESD)')
glue("average_map", fig, display=False)
plt.savefig(op.join(path_figs, 'F16_phytoplankton_mean_map.png'), dpi=300, bbox_inches='tight')

Annual average

data_y = data_xr.resample(time='1YE').mean()
fig = plot_map_subplots(data_y, 'MD50', shp_eez = shp_eez, cmap = 'YlGnBu', vmin = 0.4, vmax = 1.6, cbar = 1)

Annual anomaly

data_an = data_y - data_xr.mean(dim='time')
fig = plot_map_subplots(data_an, dataset_id, shp_eez = shp_eez, cmap='RdBu_r', vmin=-.3, vmax=.3, cbar = 1)

Average over area

dict_plot = [{'data' : data_xr.mean(dim = ['longitude', 'latitude']).to_dataframe(), 
              'var' : dataset_id, 'ax' : 1, 'label' : 'Median Phytoplankton Size - MEAN AREA'},]

fig = plot_timeseries_interactive(dict_plot, trendline=True, scatter_dict = None, figsize = (25, 12), 
                                 label_yaxes = 'Phytoplankton MD50 (µm ESD)');
fig.write_html(op.join(path_figs, 'F16_phytoplankton_mean_trend.html'), include_plotlyjs="cdn")

Timeseries at a given point

loc = [7.35, 134.48]
dict_plot = [{'data' : data_xr.sel(longitude=loc[1], latitude=loc[0], method='nearest').to_dataframe(), 
              'var' : dataset_id, 'ax' : 1, 'label' : f'Median Phytoplankton Size at [{loc[0]}, {loc[1]}]'},]

fig, ax = plot_base_map(shp_eez = shp_eez, figsize = [10, 6])
ax.set_extent([lon_range[0], lon_range[1], lat_range[0], lat_range[1]], crs=ccrs.PlateCarree())
ax.plot(loc[1], loc[0], '*', markersize = 12, color = 'royalblue', transform=ccrs.PlateCarree(), label = 'Location Analysis')
ax.legend()

<matplotlib.legend.Legend at 0x186951b80>

fig = plot_timeseries_interactive(dict_plot, trendline=True, scatter_dict = None, figsize = (25, 12),
                                 label_yaxes = 'Phytoplankton MD50 (µm ESD)');

ONI index analysis

if update_data:
    p_data = 'https://psl.noaa.gov/data/correlation/oni.data'
    df1 = download_oni_index(p_data)
    df1.to_pickle(op.join(path_data, 'oni_index.pkl'))
else:
    df1 = pd.read_pickle(op.join(path_data, 'oni_index.pkl'))

lims = [-.5, .5]
plot_oni_index_th(df1, lims = lims)

Group by ONI category

df1 = add_oni_cat(df1, lims = lims)
df1['ONI'] = df1['oni_cat']
data_xr['ONI'] = (('time'), df1.iloc[np.intersect1d(data_xr.time, df1.index, return_indices=True)[2]].ONI.values)
data_xr['ONI_cat'] = (('time'), np.where(data_xr.ONI < lims[0], -1, np.where(data_xr.ONI > lims[1], 1, 0)))
data_oni = data_xr.groupby('ONI_cat').mean()

Average

fig = plot_map_subplots(data_oni, dataset_id, shp_eez = shp_eez, cmap = 'YlGnBu', vmin = 0.8, vmax = 1.3, 
                  sub_plot= [1, 3], figsize = (20, 9),  cbar = True, cbar_pad = 0.1,
                  titles = ['La Niña', 'Neutral', 'El Niño'],)
plt.savefig(op.join(path_figs, 'F16_phytoplankton_ENSO.png'), dpi=300, bbox_inches='tight')

Anomaly

data_an = data_oni - data_xr.mean(dim='time')
fig = plot_map_subplots(data_an, dataset_id, shp_eez = shp_eez, cmap='RdBu_r', vmin=-.1, vmax=.1,
                  sub_plot= [1, 3], figsize = (20, 9),  cbar = True, cbar_pad = 0.1,
                  titles = ['La Niña', 'Neutral', 'El Niño'],)